The field for Saturday’s Kentucky Derby could be the worst in decades. Except for Uncle Mo — the champion colt whose current form is suspect and who may not get to the starting gate — not one of the 19 other entrants would rate as a serious contender in an average Derby.

Three-year-old crops vary from year to year, of course, and racing fans periodically lament the quality of the colts in the Triple Crown series. But this year’s group comes on the heels of mediocre Derby fields in 2009 and 2010, a trend that raises an uncomfortable question. While human athletes are getting bigger, stronger and faster, benefiting from improved training techniques and nutrition, are America’s thoroughbred racehorses getting worse? And, if so, why?

Andrew Beyer has been The Washington Post’s horse racing columnist since 1978 and is considered one of the leading experts on the subject. View Archive

It is an incontrovertible fact that the competition in recent Triple Crown series has been weak. Last year Super Saver was one of the least talented colts in the postwar era to earn a blanket of roses. He had won a single Grade II stakes race before the Derby, lost his three starts after the Derby and was retired. I

n 2009 the impossible long shot Mine That Bird ran away with the Derby; it was his only victory in a dozen starts as a 3- and 4-year-old.

Time is the most objective measurement of a horses’ ability, and the 3-year-olds in recent years have been slower than their counterparts in the past. Over the last quarter century, the average winning Beyer Speed Figure in the Derby has been 109. Mine That Bird’s 105 and Super Saver’s 104 were below the norm. But the slowness of this year’s field is unprecedented.

Not a single horse comes into the Derby with a figure better than 98 in his last start. Only two entrants have ever earned a triple-digit number. Uncle Mo, of course, was brilliant as a 2-year-old, earning a spectacular figure of 108 that suggested he was a superstar in the making.

I wrote that this was going to be a banner year for the Triple Crown series — not the first time I have been dead wrong about these races. Uncle Mo has apparently regressed as a 3-year-old; nobody else has stepped forward; Dialed In may be the favorite on the strength of a Florida Derby in which he earned a figure of 93. In other years a horse so slow would be a throw-out.

Part of the explanation for the decline in U.S. thoroughbreds is the exodus of well-bred horses to other countries. Arab and British buyers began dominating U.S. yearling sales in the late 1970s. Japan remade its entire thoroughbred industry with the purchase of 1989 Kentucky Derby winner Sunday Silence. Now Australians are becoming a major force at U.S. sales.

Pedigree expert Bill Oppenheim observed, “You can’t replace class. It has been leaving America and spreading around the world. American thoroughbreds appear to be getting worse, yet in the rest of the world they are getting better.” British racing fans are hailing their undefeated 3-year-old, Frankel, who earned one of the biggest Timeform ratings in history when he won the first of England’s 3-year-old classics last Saturday.

The drain of talent is not the United States’s only problem. There are still plenty of good prospects among the 30,000 or so foals born annually in this country.

But it is a well-documented fact that they aren’t as robust.

In 1960 the average American horse made 11.3 starts per year; last year that number was 6.1. Modern-day horses are unable to withstand the rigorous campaigns that were common in the past, but this appears to be a uniquely American phenomenon. As a result, some experts blame horses’ frailty on something else that’s uniquely American: the widespread use of medications in racing. “We’re the only nation on the planet that allows this stuff,” said breeder Arthur Hancock, who owned Sunday Silence. “I think these medications are weakening the breed.”

Fragile horses have short racing careers, go to stud and beget offspring who are equally fragile. The colt Indian Charlie raced a total of five times, was retired because of an injury and became a stallion. It is hardly a shock that people are now speculating about the soundness of his lightly-raced son Uncle Mo.

Recent Kentucky Derbies might be remembered differently if the contenders had stayed healthy. The 2009 race shaped up as a potentially great confrontation between I Want Revenge and Quality Road, each of whom earned Beyer Speed Figures of 113 in their prep races, but injuries knocked both out of the field.

Last year Eskendereya looked like a potential Triple Crown winner after winning the Wood Memorial, but an injury to his left foreleg ended his career abruptly. Physical problems have a sidelined a number of prominent contenders this year.

Of course, the Kentucky Derby does not necessarily reflect the status of the whole U.S. horse population. Relatively few horses today are bred to run 1¼ miles, so many talented horses may underperform at that demanding distance. Even when the 3-year-old colts are sub-par, other categories of horses may be excellent. Rachel Alexandra and Zenyatta, both of whom ended their careers last year, were two of the greatest female horses of all time. U.S. racing in recent years has hardly been bereft of talent.

Nevertheless, the 3-year-old classics are the traditional barometer of each thoroughbred generation, and they are vitally important to the sport.

The Derby, Preakness and Belmont Stakes are the last races that attract broad public interest and significant network television coverage.

Until now the Derby’s popularity has been unshakable. But if mediocrities such as Super Saver and Mine That Bird continue to win it, and if it continues to draw fields like this year’s bunch, how long can the Derby remain regarded as a great sporting event?

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